PATH freewatt HDJ, Инструкция по установке, эксплуатации и обслуживанию, Страница: 45 / 68

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15.1 MCHP Operation:
freewatt PLUS • System is designed to preferentially
provide heat to home and indirect water heater by
operating MCHP unit.
Boiler is operated as supplemental heat supply as
•
needed to maintain comfort.
Preferential operation of MCHP is achieved by
•
allowing MCHP to operate at times when thermostat
does not specifi cally call for heat, but, based on
outdoor temperature, continuing need for heat can
be established. Homeowner should expect MCHP to
“run” longer and more often than boiler, even when
thermostat may not indicate call for heat.
freewatt PLUS
• System designed to maintain close
control of building temperature. Variations in room
temperature should be less than traditional thermostats
with operating temperature dead band.
15.2 freewatt PLUS System Response to Heat
Demands:
freewatt PLUS System heating function is activated by
call for heat from thermostat or aquastat on indirect water
heater. Does not directly respond to electrical power de-
mands in home. Response of freewatt PLUS System to
heat calls follows:
Upon demand for heat from any space heating •
zone, hydronic water fl ow to zone “radiators” is
initiated, MCHP unit is started and boiler operation
is enabled. Burner in boiler will fi re as necessary to
maintain current required hydronic loop temperature
as determined by programmed outdoor reset control
of boiler. Boiler initially fi res at lowest input rate
and modulates to higher levels as determined by
temperature response of hydronic loop temperature.
Smart Zone operation of MCHP unit, initiated by call for
•
heat, will continue beyond specifi c call for heat from
Smart Zone thermostat as long as outdoor temperature
sensor indicates general need for heating of building
(i.e. outdoor temperature about 55° F). Boiler
operation is disabled immediately at end of call for heat
from Smart Zone Thermostat. Operation of MCHP unit
is terminated only when there is small temperature
rise above current set temperature of Smart Zone
Thermostat.
For other heating zones with room thermostats wired
•
directly to freewatt control module, operation of
MCHP will continue until initiating zone, or any new
heat demand zone is satisfi ed and freewatt control
module determines it is not possible to either
Operate Smart Zone without exceeding small •
temperature rise above Smart Zone setpoint or
Operate domestic water heating zone without •
causing unacceptably high temperature in MCHP
coolant. Boiler burner operation is disabled
immediately upon end of call for heat.
For zones with room thermostats wired directly to •
ECR relay control or any ECR expansion relay control,
operation of MCHP and boiler burner will terminate with
end of heat call (either from initiating zone or any other
zone.)
Call for heat by Aquastat of indirect water heating
•
tank Zone 1, when Zone 1 is confi gured for heating
of domestic water. Water heating zone pump starts,
MCHP operates, boiler burner is enabled to maintain
temperature programmed as domestic water heating
temperature (freewatt PLUS boiler parameter 1 +
33). Boiler burner is disabled and MCHP continues to
operate when Aquastat is satisfi ed, until freewatt
control module has determined it is not possible to:
Operate Smart Zone without exceeding small •
temperature rise above Smart Zone spacing heating
setpoint or
Operate domestic water heating zone without
•
causing unacceptable high temperature in MCHP
coolant.
MCHP coolant temperature is monitored internally and •
reported to freewatt control module. MCHP operation
terminates automatically by freewatt control module
and disabled for period of time ranging from 15
minutes to three hours if MCHP coolant reaches 185°F.
Occurs when current target temperature of boiler
control is high (about 160° F or above.). Can also
occur if boiler temperature boost mode is not disabled
as recommended. In either case, freewatt control
module logic takes into account frequency which 185°F
coolant temperature is reached and determines how
long to disable operation of MCHP unit. Operational
logic limits number of times MCHP is started and
stopped in presence of high hydronic loop temperature.
Default setup of
• freewatt control module provides 30
minute priority to DHW heating when DHW jumper is in
place. Priority action pertains to achieving satisfaction
of indirect water heater aquastat (not virtual heat
call operation of MCHP unit.) Priority action can be
deactivated by using Mint Service Tool.
15 - DETAILED SEQUENCE OF OPERATION